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RBloeth
Asked: 2024-09-24 02:36:11 +0800 CST

How to fix Grub this weird dual boot setup?

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I can not get Grub to show up or add Ubuntu 24.04 to the Windows 10 boot manager after fresh installs of both:

Today, I freshly installed Windows 10 on my desktop computer (after having messed up my old dual boot setup), using approximately 50% of my 500 GB SSD drive. After this was done, I freshly installed Ubuntu 24.04 on the other approximately 50% of that SSD drive, and the installation routine recognized my setup and let me choose "install next to another OS".

Now, when I boot, I either get the Windows boot manager, which only offers me to boot Windows, or I boot directly into Ubuntu, depending on my BIOS boot setup.

After having tried countless resources on the web to no avail, I gathered some data:

In my BIOS setup, I can choose between the boot modes:

  • UEFI or
  • LEGACY+UEFI (this one is selected)

In the BIOS boot options, I can choose between:

  • UEFI Hard Disk:Windows Boot Manager TA1: Crucial_CT525MX300SSD1), or
  • Hard Disk:Crucial_CT525MX300SSD1 and several others (but no "Ubuntu" or "Grub" entry available)

When I select the Windows Boot Manager, my computer boots into the Windows Boot Manager, where I can only select "Windows", which works fine.

When I select the other option "Hard Disk:Crucial_CT525MX300SSD1", then I directly boot into Ubuntu, without any boot manager.

Yet, I have several hard drives, that were all in use before when my dual boot setup was working fine (but with Ubuntu 22.04 - it was the upgrade to 24.04 that started the mess I ended up with today).

So when I look in the file manager, I see these drives (german OS, sorry for the partially german drive names):

  • Ubuntu 255.6 GB, ext4, mounted under '/' (contains /bin/, /boot/...)
  • Datenträger (= "Volume") 2.1 GB, ext4, /dev/sda2, mounted under '/media/roman/' (contains grub, vmlinuz...)
  • Datenträger 261 GB, /dev/sda5, mounted under '/media/roman/' (contains /users, /Windows - this must be the Windows system partition)
  • Volume 1.8 TB, /dev/sdb1, mounted under '/media/roman/' (contains Windows data files)
  • Datenträger (= "Volume") 2.2 TB, /ev/sdb2, mounted under '/media/roman/' (contains some old Ubuntu files, but was probably encrypted, it contains e.g. roman/Access-Your-Private.desktop, which can not be opened, and a few empty folders I used to have)
  • E_SSD 2 TB, /dev/sdc2, mounted under '/media/roman/' (contains also Windows data files)

All I understand is that obviously grub ended up on the wrong partition - at least this is what it looks like to me.

The output of the command sudo fdisk -l yields (sorry, german only):

Festplatte /dev/loop0: 4 KiB, 4096 Bytes, 8 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop1: 74,27 MiB, 77881344 Bytes, 152112 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop2: 269,77 MiB, 282873856 Bytes, 552488 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop3: 505,09 MiB, 529625088 Bytes, 1034424 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop4: 91,69 MiB, 96141312 Bytes, 187776 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop5: 10,72 MiB, 11239424 Bytes, 21952 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop6: 500 KiB, 512000 Bytes, 1000 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/loop7: 38,83 MiB, 40714240 Bytes, 79520 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes


Festplatte /dev/sda: 489,05 GiB, 525112713216 Bytes, 1025610768 Sektoren
Festplattenmodell: Crucial_CT525MX3
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes
Festplattenbezeichnungstyp: gpt
Festplattenbezeichner: 2B81319B-7259-40D2-840F-8CECE208CADA

Gerät         Anfang       Ende  Sektoren  Größe Typ
/dev/sda1       2048       4095      2048     1M BIOS boot
/dev/sda2       4096    4198399   4194304     2G Linux-Dateisystem
/dev/sda3    4198400    4403199    204800   100M EFI-System
/dev/sda4    4403200    4435967     32768    16M Microsoft reserviert
/dev/sda5    4435968  515044841 510608874 243,5G Microsoft Basisdaten
/dev/sda6  515045376  516196351   1150976   562M Windows-Wiederherstellungsumgebung
/dev/sda7  516196352 1025607679 509411328 242,9G Linux-Dateisystem


Festplatte /dev/sdb: 3,64 TiB, 4000787030016 Bytes, 7814037168 Sektoren
Festplattenmodell: WDC WD40EZRZ-00G
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 4096 Bytes
E/A-Größe (minimal/optimal): 4096 Bytes / 4096 Bytes
Festplattenbezeichnungstyp: gpt
Festplattenbezeichner: CCD52EFB-DB8E-404C-AEBB-2A46E9C5FCE3

Gerät          Anfang       Ende   Sektoren Größe Typ
/dev/sdb1        2048 3517898751 3517896704  1,6T Microsoft Basisdaten
/dev/sdb2  3517898752 7814035455 4296136704    2T Linux-Dateisystem


Festplatte /dev/sdc: 1,82 TiB, 2000398934016 Bytes, 3907029168 Sektoren
Festplattenmodell: TS2TSSD225S     
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes
Festplattenbezeichnungstyp: gpt
Festplattenbezeichner: 9B0AB42A-5CA6-40E1-BEDA-F9CCB88D50D0

Gerät      Anfang       Ende   Sektoren Größe Typ
/dev/sdc1      34      32767      32734   16M Microsoft reserviert
/dev/sdc2   32768 3907026943 3906994176  1,8T Microsoft Basisdaten


Festplatte /dev/loop8: 10,54 MiB, 11051008 Bytes, 21584 Sektoren
Einheiten: Sektoren von 1 * 512 = 512 Bytes
Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes
E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes

Setting up hard drives and partitions has always been my nightmare (as this example shows) and I really did not find any resource on the web that would help me further here - running sudo update-grub or sudo update-grub2 and trying to boot into Ubuntu from out of Windows did not change anything.

Could someone explain to me what - if at all - I could do to enable the Grub boot manager or get Ubuntu as an option into the Windows boot manager?

Any hint would be much appreciated.

boot

1 Answers

  1. Best Answer

    The issue is that I installed Windows in UEFI mode while I then installed Linux in LEGACY+UEFI mode.

    Re-installing Linux in UEFI mode solved the issue, as @mook765 stated (thank you).

    • 1